This invention relates to a strand gripper and method and more particularly to an improved gripper for transporting filling yarn in a projectile across a weaving machine.
During the operation of high speed looms the filling, whether it be a strand of wire or of yarn, is gripped between a pair of spring biased jaws for transport across the loom through the warp shed for weaving. The forces exerted in order to achieve competitive speeds cause the filling to be pulled out of the gripper. The prior art relating to grippers is exemplified by the following U.S. Pat. Nos. 3,712,345, 3,853,152, 3,854,506, and 5,441,086 which are illustrative of projectiles for Sulzer Ruti weaving machines. It will be observed that the jaws each comprise flat opposing surfaces which are spring biased toward closed position by the action of spring arms which are joined at an end remote from the jaws for fixing them within the body of the projectile. The resilient action of the spring arms is often insufficient to exert a sufficient gripping action upon the filling or weft yarns.
Efforts have been made to improve gripping characteristics by providing irregular rather than smooth opposing jaw surfaces. Irregular surfaces have been knurled, grooved, undulated as well as lined with special material. Nevertheless, problems in achieving sufficient gripping force without damaging the strands have persisted.